Urologic Surgical Procedures

This study was approved by Orlando Health Inc. (Orlando, FL) Institutional Review Board with a waiver of consent. Orlando Health Inc. is a large healthcare system (> 1,000 beds) comprised of eight facilities in central Florida, affiliated with the University of Central Florida College of Medicine and Florida State University School of Medicine. Complications identified within the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) within the Department of Urology in Orlando Health Inc. were queried retrospectively to gather information regarding patient outcomes to urologic surgeries performed from January 1, 2011 to December 31, 2011. Based on the number of procedures performed in 2011, the location of the procedures (in-patient and outpatient) and the difficulty of the procedures, CPT codes associated with 11 diverse procedures covering a wide range of urologic procedures [e.g., insertion or replacement of inflatable penile prosthesis, nephroureterectomy, partial nephrectomy, percutaneous nephrostomy tube placement, radical cystectomy, radical prostatectomy, renal/ureteral/bladder extracorporeal shockwave lithotripsy (ESWL), transurethral destruction of bladder lesion, transurethral prostatectomy, transurethral removal of ureteral obstruction, and ureteral catheterization] were queried and included for analysis. All patients identified in each of the 11 procedures were evaluated (i.e., no patient was excluded from analysis). To establish the true PMI of a procedure in an institution one would expect that >25 patients per group would be needed although the study has not yet been done to determine the exact number.
Individual medical records of the patients who underwent the above procedures were reviewed to determine the incidence of post-operative complications as defined by American College of Surgery National Surgical Quality Improvement Program (ACS NSQIP) within 30 days (any NSQIP 30-day morbidity). The ACS NSQIP complications that were noted included bleeding, superficial wound infection, deep wound infection, organ space infection, wound dehiscence, acute renal failure, progressive renal insufficiency, urinary tract infection, prolonged ileus, pneumonia, failure to wean from ventilator, unplanned intubation, pneumothorax, pulmonary embolus, cardiac arrest, exacerbation of heart failure, deep venous thrombosis, cerebrovascular accident, transient ischemic attack, sepsis, septic shock, and death (all-cause 30-day mortality). The severity of each complication was graded independently by two clinicians (JAB and RS) according to the recently validated Accordion Severity Grading System (Table 1). A third investigator (CJR) reviewed discrepancies and rendered a final score. In cases with multiple ACS NSQIP complications, the case was assigned a grade corresponding to the highest graded complication.
Next, a weighted postoperative morbidity index (PMI) was calculated as previously described [8 (link)] (i.e., to calculate the PMI for each operative procedure, the weights of all the complications for all patients who underwent the corresponding procedure were summed and divided by the total number of patients undergoing that procedure). A PMI of 0 would indicate that no patient having the procedure had any postoperative complications, while on the other hand, and a PMI of 1.000 would indicate that every patient having the procedure suffered postoperative death. In order to analyze complication severity, the sum of severity weights for all patients having any complication after a procedure were divided by the total number of patients with complications in the group (i.e., the denominator was the number of patients having a complication after the procedure, rather than the total number of patients having the procedure). Descriptive statistics were performed in Excel 2007 (Microsoft Corp).

The primary outcome was IOH, which was defined as a core temperature of < 36 °C at any time during the perioperative procedure. The candidate influencing factors are described as follows:

Demographic and baseline characteristics included sex, age, BMI, American Society of Anesthesiologists physical status, and diabetes mellitus (possibly combined with impaired thermoregulation)^{9 (link)}.

Surgery information: surgical site (thyroid, abdominal, or thoracic), blood loss, warmed or unwarmed irrigation fluid, and volume. Abdominal surgery included general, gynecological, and urological surgeries.

Anesthesia information included the volume of warmed intravenous fluid replacement, blood transfusion, and duration of anesthesia.

Other information included anesthesia induction time in the morning (8 a.m. to noon), afternoon (noon to 6 p.m.), or evening (6 p.m. to 10 p.m.); baseline core temperature, and the operating room ambient temperature.

This retrospective cohort study included patients aged ≥ 18 years who underwent noncardiac surgery, including general, gynecological, otolaryngological, plastic, and urological surgery, under general anesthesia using inhalation anesthetics (desflurane or sevoflurane) and PI monitoring from February to August 2021 in a university hospital. Patients were excluded if clinical or vital data were missing, their vital records had interruptions, or if information was lacking regarding the inhalation agent, PI, or blood pressure (noninvasive or invasive arterial pressure). To account for the differences in their clinical characteristics, patients administered desflurane and sevoflurane were matched 1:1 by propensity score. This manuscript adheres to the applicable STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guidelines^{10 (link)}.